1. Field of the Invention
The present invention relates to an image transfer apparatus used in a high-resolution printer for pressure-sensitive and heat-sensitive recording of an image on a recording sheet, and more particularly for recording an image by locally pressing and selectively heating a recording material that includes capsule.
2. Description of the Related Art
An ink is known that includes fine capsules, such as micro-capsules, filled with heat-sensitive color developing dye or ink for high-resolution printing in a high resolution color printer. A recording sheet consists of a base sheet with a layer of the micro-capsules covering the base sheet. The layer of micro-capsules includes a plurality of types of micro-capsule, each type corresponding to a specific color ink or dye, which seeps from the micro-capsule onto the recording sheet when the corresponding micro-capsule is heated to a predetermined temperature. The predetermined temperature varies dependent on the type of micro-capsule. Each seeped color ink or dye is developed and fixed by light of a predetermined wavelength, which also varies dependent on the type of micro-capsule. Therefore, each type of micro-capsule seeps a predetermined color ink or dye when heated to the redetermined temperature, and the seeped color is developed and fixed on the base sheet by irradiation with the light of the specific wavelength. Thus, ink or dye discharge to generate a full-color image, to be recorded on a recording sheet, can be controlled through selection of the micro-capsules to seep the dye or ink, which occurs through control of a localized heating and irradiation with a specific wavelength of light.
The recording process utilizing the recording sheet with the layer of the micro-capsules is complicated and time-consuming, because the localized heating and light irradiation must be repeatedly executed in order to develop and fix a plurality of colors. When the base sheet is a normal sheet of plain paper, it becomes difficult to record a high-resolution image on the base sheet, because the normal paper usually has an uneven printing surface.
Therefore, an object of the present invention is to provide a pressure-sensitive and heat-sensitive image transfer apparatus for easily recording a full-color high-resolution image on a recording sheet through control of localized pressure and temperature, regardless of a surface condition of the recording sheet.
An image transfer apparatus according to the present invention comprises an image generating unit that includes an image carrying member and a layer of micro-capsules containing dye, each micro-capsule disposed in the layer of micro-capsules exhibits a temperature/pressure characteristic such that, when the each micro-capsule is squashed under a corresponding predetermined pressure at a corresponding predetermined temperature, the dye seeps from the squashed micro-capsule and transfers to a surface of the image carrying member. An image transfer unit is also included that transfers the transferred dye as the image to a recording surface of a recording sheet.
Preferably a shell wall of the each micro-capsule is composed of a shape memory resin which exhibits a glass-transition temperature corresponding to the corresponding predetermined temperature, and a thickness of the shell wall corresponding to the corresponding predetermined pressure. Further the image transfer apparatus may include a pressing unit that presses the recording surface of the recording sheet such that the recording surface is smoothed to improve a quality of said transferred image. Also the image transfer apparatus may include a pressure application system that locally applies a predetermined pressure to the micro-capsule layer. At least one of the predetermined pressures is the corresponding predetermined pressure. A heat application system may be also included that selectively and locally heats the micro-capsule layer to predetermined temperatures. At least one of the predetermined temperatures is the corresponding predetermined temperature. The image transfer apparatus may include a capsule holding member holding the layer of micro-capsules and a recording sheet transport unit moving the recording sheet in a transport direction.
Preferably the image generating unit selectively and locally squashes and breaks the micro-capsules between the image carrying member and the capsule holding member in accordance with a control of the heat application system and the pressure application system. Further, the image carrying member may include a continuous belt, and the image generating unit may include a rotational drive system rotationally driving the continuous belt. Furthermore, the image generating unit includes a support member that supports the capsule holding member, and the image carrying member during the application of the predetermined pressures and temperatures. The image transfer unit may include a roller rotating in synchronization with a movement of the continuous belt. The roller may press the recording sheet to resiliently contact the image carrying member such that the transferred dye is accurately transferred to the recording sheet as the image.
Preferably, the image carrying member includes a platen roller, and the image transfer unit includes a rotational drive system rotationally driving the platen roller in synchronization with the movement of the recording sheet and a second roller. The second roller may presses the recording sheet to resiliently contact the image carrying member, such that the transferred dye is accurately transferred as the image to the recording sheet. Preferably, the capsule holding member disposed on the image carrying member and the image generating unit further includes an adhesion preventing member coated with a releasant that prevents adhesion of the transferred dye. Also preferably, the image generating unit selectively and locally squashes and breaks the micro-capsules between the image carrying member and the adhesive preventing member in accordance with a control of the heat application system and the pressure application system. Further, the image carrying member may include a transport drive system that drives the image carrying member so that the transferred dye is transferred as the image to the recording surface of the recording sheet. The image carrying member may be in resilient contact with the adhesion preventing member such that the adhesion preventing member rotates in synchronization with the image carrying member. Furthermore, the image transfer unit includes a rotating member that rotates in synchronization with the image carrying member. The rotating member may press the recording sheet to resiliently contact the recording surface with the capsule holding member such that the transferred dye is accurately transferred as the image to the recording surface.
An image transfer apparatus according to the present invention comprises a conveyor unit that intermittently moves a recording sheet in a transport direction, an ink-transfer ribbon that comprises a base member and a layer of micro-capsules, coated over the base member. The layer of micro-capsules contains a plurality of micro-capsules filled with dye, a shell wall of each micro-capsule of the plurality of micro-capsules being composed of resin that exhibits a temperature/pressure characteristic such that, when the each micro-capsule is squashed under a corresponding predetermined pressure at a corresponding predetermined temperature, the dye discharges from the squashed micro-capsule and transfers as the image to a recording surface of the recording sheet. A thermal head unit, performing a line by line printing operation on the base member in a recording direction substantially perpendicular to the transport direction, is included that includes a temperature application the selectively and locally heating the layer of micro-capsules to predetermined temperatures and a pressure application unit locally applying predetermined pressures to the layer of micro-capsules. The predetermined temperatures include the corresponding predetermined temperature and the predetermined pressures include the corresponding predetermined pressure. A continuous belt having a smooth outer surface is also included that resiliently contacts the layer of micro-capsules and the recording surface of the recording sheet. The continuous belt moves in synchronization with the movement of the recording sheet such that the transfer of the image to the recording surface of the recording sheet occurs.
Preferably, the plurality of micro-capsules filled with dye includes at least three types of micro-capsules that have a different shell wall breaking under the corresponding predetermined pressure at the corresponding predetermined temperature and a corresponding different color dye.
An image transfer apparatus according to the present invention comprises a conveyor unit that moves a recording sheet in a transport direction, an ink-transfer ribbon that comprises a base member and a layer of micro-capsules, coated over the base member. The layer of micro-capsules contains a plurality of micro-capsules filled with dye, a shell wall of each of the plurality of micro-capsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when the each micro-capsule is squashed under a corresponding predetermined pressure at corresponding predetermined temperature, the dye discharges from the squashed micro-capsule and transfers as the image to a recording surface of the recording sheet. A thermal head unit, performing a printing operation on the base member, is included that includes a temperature application unit selectively and locally heating the layer of micro-capsules to predetermined temperatures and a pressure application system locally applying predetermined pressures to the layer of micro-capsules. The predetermined temperatures include the corresponding predetermined temperature and the predetermined pressures include the corresponding predetermined pressure. A rotating member having a smooth outer surface is also included that resiliently contacts the layer of micro-capsules and the recording surface of the recording sheet. The rotating member moves in synchronization with the movement of the recording sheet such that the transfer of the image to the recording surface of the recording sheet occurs.
Preferably, the conveyor unit intermittently moves the recording sheet, and the thermal head performs a line by line printing operation on the base member in a recording direction substantially perpendicular to the transport direction. The thermal head and the ink-transfer ribbon may extend in parallel across substantially a width of the recording sheet. The plurality of micro-capsules filled with dye may include at least three types of micro-capsules that have a different shell wall breaking under the corresponding predetermined pressure at the corresponding predetermined temperature and a corresponding different color dye. The thermal head may be tangentially aligned with the rotating member such that the predetermined pressures are applied by the pressure application system due to the alignment.
An image transfer apparatus according to the present invention comprises a conveyor unit that moves a recording sheet in a transport direction, an ink-transfer ribbon that comprises a base member and a layer of micro-capsules, coated over the base member. The layer of the micro-capsules contains a plurality of micro-capsules filled with dye, a shell wall of each micro-capsule of said plurality of micro-capsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when each of the plurality of micro-capsules is squashed under a corresponding predetermined pressure at a corresponding predetermined temperature, the dye discharges from the squashed micro-capsule and transfers as the image to a recording surface of the recording sheet. A thermal head unit, performing a printing operation on the base member, is included that includes a temperature application unit selectively and locally heating the layer of micro-capsules to predetermined temperatures and a pressure application system locally applying predetermined pressures to the layer of micro-capsules. The predetermined temperatures include the corresponding predetermined temperature and the predetermined pressures include the corresponding predetermined pressure. A first rotating member, having a releasant coated outer surface, is also included that resiliently contacts the ink-transfer ribbon as a part of the pressure application system. A second rotating member is also included that resiliently contacts the layer of micro-capsules to the recording surface of the recording sheet. The second rotating member moves in synchronization with the movement of the recording sheet such that the transfer of the image to the recording surface of the recording sheet occurs.
Preferably, the conveyor unit intermittently moves the recording sheet, and the thermal head performs a line by line printing operation on the base member in a recording direction substantially perpendicular to the transport direction. The thermal head and the ink-transfer ribbon may extend in parallel across substantially a width of the recording sheet. And the plurality of micro-capsules filled with dye may include at least three types of micro-capsules that have a different shell wall breaking under the corresponding predetermined pressure at the corresponding predetermined temperature and a corresponding different color dye. The thermal head may be tangentially aligned with the first rotating member such that the predetermined pressures are applied by the pressure application system due to the alignment.